Absorbent structures with high strength and low md stretch

ABSTRACT

Absorbent product including a laminate of at least two plies, wherein the absorbent product has a measured Y-Connected Area parameter greater than 20 and a Surface Channel Spacing of less than 2.5 mm. The absorbent product has high strength and low machine direction stretch.

RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalApplication No. 62/842,941, filed May 3, 2019 and entitled ABSORBENTSTRUCTURES WITH HIGH STRENGH AND LOW MD STRETCH, the contents of whichare incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to absorbent structures, in particular todisposable paper towels or wipes, with unique surface topography thatresults in a product with high absorbency, high strength, and highsoftness with low machine direction stretch.

BACKGROUND

Across the globe there is great demand for disposable, absorbentstructures used for household cleaning tasks. Disposable towels andwipes meet this market demand. Disposable paper towels and wipes thatare composed of cellulosic based fibers are also nearly 100% renewableand biodegradable, thus catering to those whom are eco-conscience. Thesedisposable absorbent towels and wipes are used for a multitude of tasksthat require absorbency and strength. These tasks include absorbingliquid spills, cleaning windows and mirrors, scrubbing countertops andfloors, scrubbing and drying dishes, washing/cleaning bathroom sinks andtoilets, and even drying/cleaning hands and faces where the attribute ofsoftness becomes important. A disposable towel or wipe that can performthese demanding tasks and be produced at a price point that provides avalue proposition to the consumer is advantageous. To maintain a lowprice point, as well as conserve cellulosic based natural resources,providing for high strength and absorbency using the least amount ofmaterial is advantageous.

The industrial methods or technologies used to produce these absorbentstructures are numerous. Absorbent structures can be produced using bothWater or Air-Laid technologies. The technologies that use water to formthe cellulosic (or other natural or synthetic fiber type) webs thatcomprises the towel or wipe are called Water-Laid Technologies. Theseinclude Through Air Drying (TAD), Uncreped Through Air Drying (UCTAD),Conventional Wet Crepe (CWC), Conventional Dry Crepe (CDC), ATMOS, NTT,ETAD, and QRT. Technologies that use air to form the webs that comprisethe towel or wipe are called Air-Laid Technologies. To enhance thestrength and absorbency of these towels and wipes, more than one layerof web (or ply) can be laminated together using strictly a mechanicalprocess or preferably a mechanical process that utilizes an adhesive.

The Water-Laid technologies of Conventional Dry and Wet Crepe are thepredominant method to make these structures. These methods compriseforming a nascent web in a forming structure, transferring the web to adewatering felt where it is pressed to remove moisture, and adhering theweb to a Yankee Dryer. The web is then dried and creped from the YankeeDryer and reeled. When creped at a solids content of less than 90%, theprocess is referred to as Conventional Wet Crepe. When creped at asolids content of greater than 90%, the process is referred to asConventional Dry Crepe. These processes can be further understood byreviewing Yankee Dryer and Drying, A TAPPI PRESS Anthology, pg 215-219,which is herein incorporated by reference. These methods are wellunderstood and easy to operate at high speeds and production rates.Energy consumption per ton is low since nearly half of the water removedfrom the web is through drainage and mechanical pressing. Unfortunately,the sheet pressing also compacts the web, which lowers web thickness andresulting absorbency. A more detailed description of the ConventionalDry Crepe process follows.

The major steps of the conventional dry crepe process involve stockpreparation, forming, pressing, drying, creping, calendering (optional),and reeling the web.

The first step of stock preparation involves selection, blending,mixing, and preparation of the proper ratio of wood, plant, or syntheticfibers along with chemistry and fillers that are needed in the specifictissue grade. This mixture is diluted to over 99% water in order toallow for even fiber formation when deposited from the machine headboxinto the forming section. There are many types of forming sections usedin conventional papermaking (inclined suction breast roll, twin wireC-wrap, twin wire S-wrap, suction forming roll, and Crescent formers)but all are designed to retain the fiber, chemical, and filler recipewhile allowing the water to drain from the web. In order to accomplishthis, fabrics are utilized.

After web formation and drainage (to around 35% solids) in the formingsection (assisted by centripetal force around the forming roll, andvacuum boxes in several former types), the web is transferred to a pressfabric upon which the web is pressed between a rubber or polyurethanecovered suction pressure roll and Yankee dryer. The press fabric is apermeable fabric designed to uptake water from the web as the web ispressed in the press section. The press fabric is composed of largemonofilaments or multi-filamentous yarns, needled with fine syntheticbatt fibers to form a smooth surface for even web pressing against theYankee dryer. Removing water via pressing results in low energyconsumption.

After pressing the sheet between a suction pressure roll and a steamheated cylinder (referred to as a Yankee dryer), the web is dried fromup to 50% solids to up to 99% solids using the steam heated cylinder andhot air impingement from an air system (air cap or hood) installed overthe steam cylinder. The sheet is then creped from the steam cylinderusing a steel or ceramic doctor blade. This is a critical step in theconventional dry crepe process. The creping process greatly affectssoftness as the surface topography is dominated by the number andcoarseness of the crepe bars (finer crepe is much smoother than coarsecrepe). Some thickness and flexibility is also generated during thecreping process. If the process is a wet crepe process, the web must beconveyed between dryer fabrics through steam heated after-dryer cans todry the web to the required finished moisture content. After creping,the web is optionally calendered and reeled into a parent roll and readyfor the converting process.

The absorbency of a conventional tissue web is low due to the web beingpressed.

This results in a low bulk, low void volume web where there is littlespace for water to be absorbed. Additionally, bulk generated by crepeingis lost when the web is wetted, further reducing bulk and void volume.

The through air drying (TAD) process is another manufacturing method formaking a tissue web. The major steps of the through air drying processare stock preparation, forming, imprinting, thermal pre-drying, drying,creping, calendering (optional), and reeling the web. The stockpreparation and forming steps are similar to conventional dry creping.

Rather than pressing and compacting the web, as is performed inconventional dry crepe, the web in the TAD process undergoes the stepsof imprinting and thermal pre-drying. Imprinting is a step in theprocess where the web is transferred from a forming fabric to astructured fabric (or imprinting fabric) and subsequently pulled intothe structured fabric using vacuum (referred to as imprinting ormolding). This step imprints the weave pattern (or knuckle pattern) ofthe structured fabric into the web. This imprinting step has atremendous effect on the softness of the web, both affecting smoothnessand the bulk structure. The design parameters of the structured fabric(weave pattern, mesh, count, warp and weft monofilament diameters,caliper, air permeability, and optional over-laid polymer) are,therefore, important to the development of web softness. Themanufacturing method of an imprinting/structuring fabric is similar to aforming fabric (see U.S. Pat. Nos. 3,473,576; 3,573,164; 3,905,863;3,974,025; and 4,191,609 for examples) except for an additional step ifan overlaid polymer is utilized. These types of fabrics are disclosedin, for example, U.S. Pat. Nos. 6,120,642; 5,679,222; 4,514,345;5,334,289; 4,528,239; and 4,637,859. Essentially, fabrics produced usingthese methods result in a fabric with a patterned resin applied over awoven substrate. The benefit is that resulting patterns are not limitedby a woven structure and can be created in any desired shape to enable ahigher level of control of the web structure and topography that dictateweb quality properties.

After imprinting, the web is thermally pre-dried by moving hot airthrough the web while it is conveyed on the structured fabric. Thermalpre-drying can be used to dry the web to over 90% solids before it istransferred to a steam heated cylinder. The web is then transferred fromthe structured fabric to the steam heated cylinder though a very lowintensity nip (up to 10 times less than a conventional press nip)between a solid pressure roll and the steam heated cylinder. The onlyportions of the web that are pressed between the pressure roll and steamcylinder rest on knuckles of the structured fabric, thereby protectingmost of the web from the light compaction that occurs in this nip. Thesteam cylinder and an optional air cap system, for impinging hot air,then dry the sheet to up to 99% solids during the drying stage beforecreping occurs. The creping step of the process again only affects theknuckle sections of the web that are in contact with the steam cylindersurface. Due to only the knuckles of the web being creped, along withthe dominant surface topography being generated by the structuredfabric, and the higher thickness of the TAD web, the creping process hasmuch smaller effect on overall softness as compared to conventional drycrepe. After creping, the web is optionally calendered and reeled into aparent roll and ready for the converting process. Some TAD machinesutilize fabrics (similar to dryer fabrics) to support the sheet from thecrepe blade to the reel drum to aid in sheet stability and productivity.Creped through air dried products are disclosed in, for example, U.S.Pat. Nos. 3,994,771; 4,102,737; 4,529,480; and 5,510,002.

The TAD process is generally higher in capital costs than a conventionaltissue machine due to the amount of air handling equipment needed forthe TAD section with higher energy consumption from burning natural gasor other fuels for thermal pre-drying. The bulk softness and absorbencyis superior to conventional paper due to the superior bulk generationvia structured fabrics which creates a low density, high void volume webthat retains its bulk when wetted. The surface smoothness of a TAD webcan approach that of a conventional tissue web. The productivity of aTAD machine is less than that of a conventional tissue machine due tothe complexity of the process and especially the difficulty in providinga robust and stable coating package on the Yankee dryer needed fortransfer and creping of a delicate pre-dried web.

A variation of the TAD process where the sheet is not creped, but ratherdried to up to 99% using thermal drying and blown off the structuredfabric (using air) to be optionally calendered and reeled also exits.This process is called UCTAD or un-creped through air drying process. Anuncreped through air dried product is disclosed in U.S. Pat. No.5,607,551.

A new process/method and paper machine system for producing tissue hasbeen developed by the Voith company and is being marketed under the nameATMOS. The process/method and paper machine system have several patentedvariations, but all involve the use of a structured fabric inconjunction with a belt press. The major steps of the ATMOS process andits variations are stock preparation, forming, imprinting, pressing(using a belt press), creping, calendering (optional), and reeling theweb.

The stock preparation step is the same as that used in a conventional orTAD machine. The purpose is to prepare the proper recipe of fibers,chemical polymers, and additives that are necessary for the grade oftissue being produced, and diluting this slurry to allow for proper webformation when deposited out of the machine headbox (single, double, ortriple layered) to the forming surface. The forming process can utilizea twin wire former (as described in U.S. Pat. No. 7,744,726) a CrescentFormer with a suction Forming Roll (as described in U.S. Pat. No.6,821,391), or preferably a Crescent Former (as described in U.S. Pat.No. 7,387,706). The preferred former is provided a slurry from theheadbox to a nip formed by a structured fabric (inner position/incontact with the forming roll) and forming fabric (outer position). Thefibers from the slurry are predominately collected in the valleys (orpockets, pillows) of the structured fabric and the web is dewateredthrough the forming fabric. This method for forming the web results in aunique bulk structure and surface topography as described in U.S. Pat.No. 7,387,706 (FIG. 1 through FIG. 11). The fabrics separate after theforming roll with the web staying in contact with the structured fabric.At this stage, the web is already imprinted by the structured fabric,but utilization of a vacuum box on the inside of the structured fabriccan facilitate further fiber penetration into the structured fabric anda deeper imprint.

The web is now transported on the structured fabric to a belt press. Thebelt press can have multiple configurations. The first patented beltpress configurations used in conjunction with a structured fabric can beviewed in U.S. Pat. No. 7,351,307 (FIG. 13), where the web is pressedagainst a dewatering fabric across a vacuum roll by an extended nip beltpress. The press dewaters the web while protecting the areas of thesheet within the structured fabric valleys from compaction. Moisture ispressed out of the web, through the dewatering fabric, and into thevacuum roll. The press belt is permeable and allows for air to passthrough the belt, web, and dewatering fabric, and into the vacuum roll,thereby enhancing the moisture removal. Since both the belt anddewatering fabric are permeable, a hot air hood can be placed inside ofthe belt press to further enhance moisture removal as shown in FIG. 14of U.S. Pat. No. 7,351,307. Alternately, the belt press can have apressing device arranged within the belt which includes several pressshoes, with individual actuators to control cross direction moistureprofile (see FIG. 28 of U.S. Pat. Nos. 7,951,269 or 8,118,979 or FIG. 20of U.S. Pat. No. 8,440,055) or a press roll (see FIG. 29 of U.S. Pat.No. 7,951,269 or 8,118,979 or FIG. 21 of U.S. Pat. No. 8,440,055). Thepreferred arrangement of the belt press has the web pressed against apermeable dewatering fabric across a vacuum roll by a permeable extendednip belt press. Inside the belt press is a hot air hood that includes asteam shower to enhance moisture removal. The hot air hood apparatusover the belt press can be made more energy efficient by reusing aportion of heated exhaust air from the Yankee air cap or recirculating aportion of the exhaust air from the hot air apparatus itself (see U.S.Pat. No. 8,196,314). Further embodiments of the drying system composedof the hot air apparatus and steam shower in the belt press section aredescribed in U.S. Pat. Nos. 8,402,673, 8,435,384 and 8,544,184.

After the belt press is a second press to nip the web between thestructured fabric and dewatering felt by one hard and one soft roll. Thepress roll under the dewatering fabric can be supplied with vacuum tofurther assist water removal. This preferred belt press arrangement isdescribed in U.S. Pat. Nos. 8,382,956, and 8,580,083, with FIG. 1showing the arrangement. Rather than sending the web through a secondpress after the belt press, the web can travel through a boost dryer(FIG. 15 of U.S. Pat. Nos. 7,387,706 or 7,351,307), a high pressurethrough air dryer (FIG. 16 of U.S. Pat. Nos. 7,387,706 or 7,351,307), atwo pass high pressure through air dryer (FIG. 17 of U.S. Pat. Nos.7,387,706 or 7,351,307) or a vacuum box with hot air supply hood (FIG. 2of U.S. Pat. No. 7,476,293). U.S. Pat. Nos. 7,510,631, 7,686,923,7,931,781 8,075,739, and 8,092,652 further describe methods and systemsfor using a belt press and structured fabric to make tissue productseach having variations in fabric designs, nip pressures, dwell times,etc. and are mentioned here for reference. A wire turning roll can bealso be utilized with vacuum before the sheet is transferred to a steamheated cylinder via a pressure roll nip (see FIG. 2a of U.S. Pat. No.7,476,293).

The sheet is now transferred to a steam heated cylinder via a presselement. The press element can be a through drilled (bored) pressureroll (FIG. 8 of U.S. Pat. No. 8,303,773), a through drilled (bored) andblind drilled (blind bored) pressure roll (FIG. 9 of U.S. Pat. No.8,303,773), or a shoe press (see U.S. Pat. No. 7,905,989). After the webleaves this press element to the steam heated cylinder, the % solids arein the range of 40-50% solids. The steam heated cylinder is coated withchemistry to aid in sticking the sheet to the cylinder at the presselement nip and to also aid in removal of the sheet at the doctor blade.The sheet is dried to up to 99% solids by the steam heated cylinder andinstalled hot air impingement hood over the cylinder. This dryingprocess, the coating of the cylinder with chemistry, and the removal ofthe web with doctoring is explained in U.S. Pat. Nos. 7,582,187 and7,905,989. The doctoring of the sheet off the Yankee, creping, issimilar to that of TAD with only the knuckle sections of the web beingcreped. Thus, the dominant surface topography is generated by thestructured fabric, with the creping process having a much smaller effecton overall softness as compared to conventional dry crepe. The web isthen calendered (optional,) slit, and reeled and ready for theconverting process.

The ATMOS process has capital costs between that of a conventionaltissue machine and TAD machine. It has more fabrics and a more complexdrying system compared to a conventional machine, but less equipmentthan a TAD machine. The energy costs are also between that of aconventional and TAD machine due to the energy efficient hot air hoodand belt press. The productivity of the ATMOS machine has been limiteddue to the ability of the novel belt press and hood to dewater the weband poor web transfer to the Yankee dryer, likely driven by poorsupported coating packages, the inability of the process to utilizestructured fabric release chemistry, and the inability to utilizeoverlaid fabrics to increase web contact area to the dryer. Pooradhesion of the web to the Yankee dryer has resulted in poor creping andstretch development which contributes to sheet handling issues in thereel section. The result is that the production of an ATMOS machine iscurrently below that of a conventional and TAD machine. The bulksoftness and absorbency is superior to conventional, but lower than aTAD web since some compaction of the sheet occurs within the belt press,especially areas of the web not protected within the pockets of thefabric. Also, bulk is limited since there is no speed differential tohelp drive the web into the structured fabric as exists on a TADmachine. This severely limits the ability to produce a bulky, absorbentpaper towel. The surface smoothness of an ATMOS web is between that of aTAD web and conventional web primarily due to the current limitation onuse of overlaid structured fabrics.

The ATMOS manufacturing technique is often described as a hybridtechnology because it utilizes a structured fabric like the TAD process,but also utilizes energy efficient means to dewater the sheet like theConventional Dry Crepe process. Other manufacturing techniques whichemploy the use of a structured fabric along with an energy efficientdewatering process are the ETAD process and NTT process.

The ETAD process and products can be viewed in U.S. Pat. Nos. 7,339,378,7,442,278, and 7,494,563. This process can utilize any type of formersuch as a Twin Wire Former or Crescent Former. After formation andinitial drainage in the forming section, the web is transferred to apress fabric where it is conveyed across a suction vacuum roll for waterremoval, increasing web solids up to 25%. Then the web travels into anip formed by a shoe press and backing/transfer roll for further waterremoval, increasing web solids up to 50%. At this nip, the web istransferred onto the transfer roll and then onto a structured fabric viaa nip formed by the transfer roll and a creping roll. At this transferpoint, speed differential can be utilized to facilitate fiberpenetration into the structured fabric and build web caliper. The webthen travels across a molding box to further enhance fiber penetrationif needed. The web is then transferred to a Yankee dryer where it can beoptionally dried with a hot air impingement hood, creped, calendared,and reeled.

The ETAD process to date has been reported to have severe productivity,quality, and cost problems. Poor energy efficiency has been reported,bulk has been difficult to generate (likely due to high web dryness atthe point of transfer to the structured fabric), and softness has beenpoor (coarse fabrics have been utilized to generate target bulk, therebydecreasing surface smoothness). Absorbency is better than ATMOS due tothe ability to utilize speed differential to build higher bulk, but itis still below that of TAD which can create higher bulk with limited webcompaction that would otherwise reduce void volume and thus absorbency.The installed costs of an ETAD machine are likely close to that of a TADmachine due to the large amount of fabrics and necessary supportingequipment.

The NTT process and products can be viewed in international patentapplication publication WO 2009/061079 A1, and U.S. Patent ApplicationPublication Nos. US 2011/0180223 A1 and US 2010/0065234 A1. The processhas several embodiments, but the key step is the pressing of the web ina nip formed between a structured fabric and press felt. The webcontacting surface of the structured fabric is a non-woven material witha three dimensional structured surface comprised of elevations anddepressions of a predetermined size and depth. As the web is passedthrough this nip, the web is formed into the depression of thestructured fabric since the press fabric is flexible and will reach downinto all of the depressions during the pressing process. When the feltreaches the bottom of the depression, hydraulic force is built up whichforces water from the web and into the press felt. To limit compactionof the web, the press rolls will have a long nip width which can beaccomplished if one of the rolls is a shoe press. After pressing, theweb travels with the structured fabric to a nip with the Yankee dryer,where the sheet is optionally dried with a hot air impingement hood,creped, calendared, and reeled.

The NTT process has low capital costs, equal or slightly higher than aconventional tissue machine. It has high production rates (equal orslightly less than a conventional machine) due to the simplicity ofdesign, the high degree of dewatering of the web at the shoe press, andthe novelty of construction of the structured fabric. The structuredfabric, which will be described later in this document, provides asmooth surface with high contact area to the dryer for efficient webtransfer. This high contact area and smooth surface makes the Yankeecoating package much easier to manage and creates conditions beneficialfor fine creping, resulting in good sheet handling in the reel section.The bulk softness of the NTT web is not equal to the ATMOS sheet as theweb is highly compacted inside the structured fabric by the press feltcompared to the ATMOS web. The surface smoothness is better than anATMOS web due to the structured fabric design providing for bettercreping conditions. The NTT process also does not have a speeddifferential into the structured fabric so the bulk and absorbencyremains below the potential of the TAD and ETAD processes.

The QRT process is disclosed in US 2008/0156450 A1 and U.S. Pat. No.7,811,418. The process can utilize a twin wire former to form the webwhich is then transferred to a press fabric or directly formed onto apress fabric using an inverted Crescent former. The web can be dewateredacross a suction turning roll in the press section before being pressedin an extended nip between the press fabric and a plain transfer belt. Arush transfer nip is utilized to transfer the web to a structured fabricin order to build bulk and mold the web before the web is transferred tothe Yankee dryer and creped. This process alleviates the NTT designdeficiency which lacks a rush transfer or speed differential to forcethe web into the structured fabric to build bulk. However, the costs,complexity, and likely productivity will be negatively affected.

Absorbent structures are also made using the Air-Laid process. Thisprocess spreads the cellulosic, or other natural or synthetic fibers, inan air stream that is directed onto a moving belt. These fibers collecttogether to form a web that can be thermally bonded or spray bonded withresin and cured. Compared to Wet-Laid, the web is thicker, softer, moreabsorbent and also stronger. It is known for having a textile-likesurface and drape. Spun-Laid is a variation of the Air-Laid process,which produces the web in one continuous process where plastic fibers(polyester or polypropylene) are spun (melted, extruded, and blown) andthen directly spread into a web in one continuous process. Thistechnique has gained popularity as it can generate faster belt speedsand reduce costs.

To further enhance the strength of the absorbent structure, more thanone layer of web (or ply) can be laminated together using strictly amechanical process or preferably a mechanical process that utilizes anadhesive. It is generally understood that a multi-ply structure can havean absorbent capacity greater than the sum of the absorbent capacitiesof the individual single plies. Without being bound by theory, it isthought this difference is due to the inter-ply storage space created bythe addition of an extra ply. When producing multi-ply absorbentstructures, it is important that the plies are bonded together in amanner that will hold up when subjected to the forces encountered whenthe structure is used by the consumer. Scrubbing tasks such as cleaningcountertops, dishes, and windows all impart forces upon the structurewhich can cause the structure to rupture and tear. When the bondingbetween plies fails, the plies move against each other, therebyimparting frictional forces at the ply interface. This frictional forceat the ply interface can induce failure (rupture or tearing) of thestructure, thus reducing the overall effectiveness of the product toperform scrubbing and cleaning tasks.

There are many methods used to join or laminate multiple plies of anabsorbent structure to produce a multi-ply absorbent structure. Onemethod commonly used is embossing. Embossing is typically performed byone of three processes: tip to tip (or knob to knob), nested, or rubberto steel DEKO embossing. Tip to tip embossing is illustrated by commonlyassigned U.S. Pat. No. 3,414,459, while nested embossing process isillustrated in U.S. Pat. No. 3,556,907. Rubber to steel DEKO embossingcomprises a steel roll with embossing tips opposed to a pressure roll,sometimes referred to as a backside impression roll, having anelastomeric roll cover wherein the two rolls are axially parallel andjuxtaposed to form a nip where the embossing tips of the emboss rollmesh with the elastomeric roll cover of the opposing roll through whichone sheet passes and a second unembossed sheet is laminated to theembossed sheet using a marrying roll nipped to the steel embossing roll.In an exemplary rubber to steel embossing process, an adhesiveapplicator roll may be aligned in an axially parallel arrangement withthe patterned embossing roll, such that the adhesive applicator roll isupstream of the nip formed between the emboss and pressure roll. Theadhesive applicator roll transfers adhesive to the embossed web on theembossing roll at the crests of the embossing knobs. The crests of theembossing knobs typically do not touch the perimeter of the opposingidler roll at the nip formed therebetween, necessitating the addition ofa marrying roll to apply pressure for lamination.

Other attempts to laminate absorbent structure webs include bonding theplies at junction lines wherein the lines include individual pressurespot bonds. The spot bonds are formed using a thermoplastic lowviscosity liquid such as melted wax, paraffin, or hot melt adhesive, asdescribed in U.S. Pat. No. 4,770,920. Another method laminates webs ofabsorbent structure by thermally bonding the webs together usingpolypropylene melt blown fibers as described in U.S. Pat. No. 4,885,202.Other methods use metlblown adhesive applied to one face of an absorbentstructure web in a spiral pattern, stripe pattern, or random patternbefore pressing the web against the face of a second absorbent structureas described in U.S. Pat. Nos. 3,911,173, 4,098,632, 4,949,688,4,891249, 4,996,091 and 5,143,776.

There is a continuing need for absorbent products that are moreefficient and have increased absorbency. It would also be advantageousto develop softness, absorbency, and strength without needing highlevels of machine direction (“MD”) stretch.

SUMMARY OF THE INVENTION

An object of this invention is to utilize a structuring fabric on a TADasset to produce laminated absorbent structures with previouslyunattainable levels of high ball burst strength, absorbency, andsoftness at particularly low MD stretch.

An absorbent product according to an exemplary embodiment of the presentinvention includes a laminate of at least two plies, wherein theabsorbent product has a measured Y-Connected Area parameter greater than20 and a Surface Channel Spacing of less than 2.5 mm. The ability toachieve these quality characteristics at low MD stretch values allowsfor improved productivity and lower costs. Without being bound bytheory, this is because high levels of MD stretch generally require useof high levels of rush transfer (differential transfer velocity, wetcrepe, wire crepe), which involves running differential speed betweenfabrics or machine elements in the drying section, as previouslydetailed in the Background. One may also choose to run high levels ofdry crepe to generate MD stretch which involves running speeddifferential between the Yankee dryer and Reeling device, as previouslydetailed in the Background. Speed differential has the negative impactof reducing the speed of the production asset and thus limitsproductivity. Speed differential also decreases tensile strength of theproduct, which must be compensated for by increasing chemical strengthadditives or increasing mechanical fibrillation of the fibrous materialsto improve bonding between fibers. Mechanical fibrillation of the fibersreduces the ability of the fibrous web to drain in the forming section,increasing drying and associated energy costs. Addition of chemicaladditives to improve strength also has the direct effect of increasingraw material costs. Therefore, limiting the need for generation of MDstretch provides for a productivity and cost benefit for themanufacturer. As used herein, “low MD stretch” means a stretch of about20% to about 8%, or 15% to 8%, or 12% to 8%, or about 11% to about 8%.As used herein, “high strength” means a tensile strength of from about370 N/m to about 550 N/m.

An absorbent product according to an exemplary embodiment of the presentinvention comprises a laminate of at least two plies, wherein theabsorbent product has a measured Y-Connected Area parameter greater than20, a Surface Channel Spacing of less than 2.5 mm, and a CD wet tensilestrength of greater than 80 N/m.

According to an exemplary embodiment, the absorbent product has anabsorbency of greater than 12.2 grams of water per gram of the absorbentproduct.

According to an exemplary embodiment, the absorbent product has a ballburst to MD stretch ratio of greater than 100.

According to an exemplary embodiment, the absorbent product has anabsorbency to MD stretch ratio of greater than 1.2.

According to an exemplary embodiment, the absorbent product has asoftness to MD stretch ratio of greater than 4.75.

According to an exemplary embodiment, (softness X ball burst)/MD stretchof the absorbent product has a value greater than 4800.

According to an exemplary embodiment, (ball burst X absorbency)/MDstretch of the absorbent product has a value greater than 1250.

According to an exemplary embodiment, (softness X absorbency)/(MDstretch) of the absorbent product has a value greater than 60.

According to an exemplary embodiment, the product comprises a surfacehaving channels, and the channels have a channel angle between 5 and 25degrees.

According to an exemplary embodiment, the product comprises a surfacehaving channels, and the channels have a channel depth between 0.60 mmto 0.80 mm.

According to an exemplary embodiment, the absorbent structure isproduced using a wet laid TAD process.

According to an exemplary embodiment, at least one of the at least twoplies comprise cellulosic-based fibers.

According to an exemplary embodiment, the cellulosic-based fibers areselected from the group consisting of wood pulp, cannabis, cotton,regenerated or spun cellulose, jute, flax, ramie, bagasse, kenaf fibersand combinations thereof.

According to an exemplary embodiment, at least one of the at least twoplies comprise synthetic fibers.

According to an exemplary embodiment, the synthetic fibers are made froma polymer selected from the group consisting of polyolefin, polyester,polypropylene and polylactic acid.

According to an exemplary embodiment, at least one of the two pliescomprise synthetic fibers.

According to an exemplary embodiment, the synthetic fibers are made froma polymer selected from the group consisting of polyolefin, polyester,polypropylene and polylactic acid.

According to an exemplary embodiment, the absorbent product comprisesboth synthetic and cellulosic based polymers.

According to an exemplary embodiment, each of the at least two plies areembossed and the at least two plies are adhered together.

According to an exemplary embodiment, the at least two plies are adheredtogether with a water-soluble adhesive mixture selected from the groupconsisting of polyvinyl alcohol, polyvinyl acetate, starch based resinsand mixtures thereof.

According to an exemplary embodiment, the water-soluble adhesive isapplied to at least one ply of the at least two plies at a temperaturewithin a range of 32 degrees C. to 66 degrees C.

According to an exemplary embodiment, the water-soluble adhesive mixturefurther comprises a water soluble cationic resin selected from the groupconsisting of polyamide-epichlorohydrin resins, glyoxalatedpolyacrylamide resins, polyethyleneimine resins, polyethylenimineresins, and mixtures thereof.

According to an exemplary embodiment, each of the at least two pliescomprise an embossed area, wherein the embossed area occupies betweenapproximately 5 to 15% of the total surface area of a surface of theply.

According to an exemplary embodiment, each of the at least two pliescomprise an embossed area having a surface, wherein a depth ofembossment of the surface is between approximately 0.28 and 0.43centimeters.

According to an exemplary embodiment, each of the at least two pliescomprise an embossed area having a surface, wherein each embossment ofthe surface is between approximately 0.04 and 0.08 square centimeters insize.

According to an exemplary embodiment, the absorbent product is a papertowel, a disposable towel or wipe, a bath or facial tissue, or anonwoven product.

A two ply disposable towel according to an exemplary embodiment of thepresent invention has a ball burst to MD stretch ratio of greater than100.

A two ply disposable towel according to an exemplary embodiment of thepresent invention has an absorbency to MD stretch ratio of greater than1.2

A two ply disposable towel according to an exemplary embodiment of thepresent invention has a softness to MD stretch ratio of greater than4.75.

A two ply disposable towel according to an exemplary embodiment of thepresent invention has a (softness X ball burst)/MD stretch value greaterthan 4800.

A two ply disposable towel according to an exemplary embodiment of thepresent invention has a (ball burst X absorbency)/MD stretch valuegreater than 1250.

A two ply disposable towel according to an exemplary embodiment of thepresent invention has a Str value less than 0.15.

A two ply disposable towel according to an exemplary embodiment of thepresent invention has an Str value of less than 0.15 and a Channel Anglegreater than 2 degrees.

According to an exemplary embodiment, a basis weight of the product isless than 43 grams per square meter.

According to an exemplary embodiment, a basis weight of the product isless than 50 grams per square meter.

According to an exemplary embodiment, the absorbent product has an Strvalue less than 0.15.

According to an exemplary embodiment, the absorbent product has an Strvalue of less than 0.15 and a Channel Angle greater than 2 degrees.

A two-ply, through air dried disposable paper towel product according toan exemplary embodiment of the present invention comprises a laminate ofat least two plies, wherein the product has a measured Y-Connected Areaparameter greater than 20, a Surface Channel Spacing of less than 2.5mm, and a CD wet tensile strength of greater than 80 N/m.

According to an exemplary embodiment, the product has a ball burst to MDstretch ratio of greater than 100.

According to an exemplary embodiment, the product has an absorbency toMD stretch ratio of greater than 1.2.

According to an exemplary embodiment, (ball burst X absorbency)/MDstretch of the product has a value greater than 1250.

According to an exemplary embodiment, the paper towel product comprisesa surface having channels, and the channels have a channel angle between5 and 25 degrees.

According to an exemplary embodiment, the paper towel product comprisesa surface having channels, and the channels have a channel depth between0.60 mm to 0.80 mm.

According to an exemplary embodiment, the product has an Str value lessthan 0.15.

According to an exemplary embodiment, the paper towel product comprisesa surface having channels, and the product has an Str value of less than0.15 and a channel angle greater than 2 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of exemplary embodiments of the presentinvention will be more fully understood with reference to the following,detailed description when taken in conjunction with the accompanyingfigures, wherein:

FIG. 1 is a micrograph of a TAD fabric used to form an absorbentstructure according to an exemplary embodiment of the present invention;

FIG. 2 is a block diagram of a system for manufacturing a ply of anabsorbent structure according to an exemplary embodiment of the presentinvention;

FIG. 3 is a block diagram of a system for laminating plies according toan exemplary embodiment of the present invention;

FIG. 4 is a micrograph of an absorbent structure according to anexemplary embodiment of the present invention;

FIG. 5 showing a conventional crepe blade;

FIG. 6 shows a crepe blade according to an exemplary embodiment of thepresent invention;

FIG. 7 are tables providing test result data for various attributes ofspecific examples of the inventive absorbent structure as compared tocommercial products;

FIG. 8 show selections made within a user interface of a GATS machine tomeasure absorbency;

FIG. 9 shows pre-processing settings used on a Keyence Macroscopic tomeasure Y-Connected Area and Surface Channel Spacing;

FIG. 10 shows geometry settings used on a Keyence Macroscopic to measureY-Connected Area and Surface Channel Spacing;

FIG. 11 show filtering setting used on a Keyence Macroscopic to measureY-Connected Area and Surface Channel Spacing;

FIG. 12 is a micrograph of an absorbent structure showing Y-ConnectedArea;

FIG. 13 are micrographs of an absorbent structure showing texture aspectratio;

FIG. 14 is a photo showing measurement of channel angle of an absorbentstructure;

FIG. 15 shows images from a Keyence Macroscopic illustrating measurementof channel depth; and

FIG. 16 shows an emboss pattern according to an exemplary embodiment ofthe present invention.

DETAILED DESCRIPTION

A laminate according to an exemplary embodiment of the present inventionis composed of two or more webs/plies of absorbent structures laminatedtogether in a face-to face relationship using a heated aqueous adhesive.The laminate exhibits previously unattainable levels of ball burststrength, absorbency, and softness at particularly low levels of MDstretch. Each ply or a single ply may have a plurality of embossmentsprotruding outwardly from the plane of the ply towards the adjacent ply.If a three ply product is produced, the central ply may have embossmentsextending outwardly in both directions.

The absorbent structures can be manufactured by any Wet-Laid or Air-Laidmethods. The materials used to produce the disposable structured tissueor paper towel product can be fibers in any ratio selected fromcellulosic-based fibers, such as wood pulps (softwood gymnosperms orhardwood angiosperms), cannabis, cotton, regenerated or spun cellulose,jute, flax, ramie, bagasse, kenaf, or other plant based cellulosic fibersources. Synthetic fibers, such as a polyolefin (e.g., polypropylene),polyester, or polylactic acid can also be used. Each ply of a multi-plyabsorbent product of the present invention may comprise cellulosic basedfibers and/or synthetic fibers. Also, any of the plies may be layeredwith a different fiber composition in each layer. Such a layering offibers can be produced using a multilayered headbox on a wet laid asset,such as a TAD paper machine.

FIG. 2 is a block diagram of a system for manufacturing a three-layeredply of an absorbent structure according to an exemplary embodiment ofthe present invention. The system 100 includes a first exterior layerfan pump 102, a core layer fan pump 104, a second exterior layer fanpump 106, a headbox 108, a forming section 110, a drying section 112 anda calender section 114. The first and second exterior layer fan pumps102, 106 deliver the pulp mixes of the first and second external layersto the headbox 108, and the core layer fan pump 104 delivers the pulpmix of the core layer to the headbox 108. As is known in the art, theheadbox delivers a wet web of pulp onto a forming wire within theforming section 110. The wet web is then laid on the forming wire withthe core layer disposed between the first and second external layers.

Wet end additives may be mixed with the pulp prior to delivery to theheadbox. To impart wet strength to the absorbent structure in the wetlaid process, typically a cationic strength component is added to thefurnish during stock preparation. The cationic strength component caninclude any polyethyleneimine, polyethylenimine,polyaminoamide-epihalohydrin (preferably epichlorohydrin),polyamine-epichlorohydrin, polyamide, or polyvinylamide wet strengthresin. Useful cationic thermosetting polyaminoamide-epihalohydrin andpolyamine-epichlorohydrin resins are disclosed in U.S. Pat. Nos.2,926,154, 3,049,469, 3,058,873, 3,066,066, 3,125,552, 3,186,900,3,197,427, 3,224,986, 3,224,990, 3,227,615, 3,240,664, 3,813,362,3,778,339, 3,733,290, 3,227,671, 3,239,491, 3,240,761, 3,248,280,3,250,664, 3,311,594, 3,329,657, 3,332,834, 3,332,901, 3,352,833,3,248,280, 3,442,754, 3,459,697, 3,483,077, 3,609,126, 4,714,736,3,058,873, 2,926,154, 3,855,158, 3,877,510, 4,515,657, 4,537,657,4,501,862, 4,147,586, 4,129,528, 5,082,527, 5,239,047, 5,318,669,5,502,091, 5,525,664, 5,614,597, 5,633,300, 5,656,699, 5,674,358,5,904,808, 5,972,691, 6,179,962, 6,355,137, 6,376,578, 6,429,253,7,175,740, and 7,291,695 all of which are hereby incorporated byreference.

To impart capacity of the cationic strength resins, it is well known inthe art to add water soluble carboxyl containing polymers to the furnishin conjunction with the cationic resin. Suitable carboxyl containingpolymers include carboxymethylcellulose (CMC) as disclosed in U.S. Pat.Nos. 3,058,873, 3,049,469 and 3,998,690. Anionic polyacrylamide (APAM)polymers are an alternative to using carboxyl containing polymers toimprove wet strength development in conjunction with cationic strengthresins as disclosed in U.S. Pat. Nos. 3,049,469 and 6,939,443. If APAMis utilized rather than CMC, then cellulase enzymes can be utilized tobuild strength without concern for the enzymes reacting with the CMC tocleave bonds and shorten the degree of polymerization of the molecule,rendering it much less effective. The three types of cellulase enzymesthat could be utilized include endo-cellulases, exo-cellulases, andcellobiase cellulases.

To impart dry strength, polymers belonging to any one of the followingthree categories can be mixed in the furnish separately or incombinations thereof: (i) polymers capable of only forming hydrogenbonds to cellulose fibers such as starch or certain polyacrylamides,(ii) polymers capable of additionally forming ionic bonds to cellulosefibers such as higher cationic polyvinylamines or (iii) polymers capableof covalently bonding to the cellulose fibers such as glyoxylatedpolyacrylamide. The polymers can be synthetic or natural. The polymerscan be cationic, or anionic, or amphoteric. The polymers can becopolymers, linear or branched structures. In addition to amphotericstarch, suitable dry strength additives may include but are not limitedto starch and starch derivatives, glyoxalated polyacrylamide,carboxymethylcellulose, guar gum, locust bean gum, cationicpolyacrylamide, polyvinyl alcohol, anionic polyacrylamide,styrene-butadiene copolymers, vinyl acetate polymers, ethylene-vinylacetate copolymers, vinyl chloride polymers, vinylidene chloridepolymers, vinyl chloride-vinylidene copolymers, acrylo-nitrilecopolymers, acrylic emulsions, styrene-butadiene latexes, elastomericlatex emulsions, ethylene-acrylic copolymers or combinations thereof.Exemplary materials for use as dry strength additives include thosedisclosed in U.S. Pat. Nos. 3,556,932, 3,556,933, 4,035,229, 4,129,722,4,217,425, 5,085,736, 5,320,711, 5,674,362, 5,723,022, 6,224,174,6,245,874, 6,749,721, 7,488,403, 7,589,153, 7,828,934, 7,897013,4,818,341, 4,940,514, 4,957,977, 6,616,807, 7,902,312, and 7,922,867 allof which are hereby incorporated by reference in their entirety.

After formation in the forming section 110, the partially dewatered webis transferred to the drying section 112. Within the drying section 112,the tissue may be dried using through air drying processes which involvethe use of a structured fabric. In an exemplary embodiment, the tissueis dried to a moisture content of about 7 to 20% using a through airdrier manufactured by Valmet Corporation, of Espoo, Finland. In anotherexemplary embodiment, two or more through air drying stages are used inseries. However, it should be emphasized that this is only one ofvarious methods of manufacturing an absorbent structure to be used inmanufacturing the laminate of the present invention.

In an exemplary embodiment, the tissue of the present invention ispatterned during the through air drying process using a TAD fabric. FIG.1 shows a TAD fabric, generally designated by reference number 1000,that may be used in a TAD drying process according to an exemplaryembodiment of the present invention. The TAD fabric 1000 has thefollowing attributes:

Round warp yarn 1004 in the machine direction with a diameter in therange of 0.35 mm to 0.45 mm or flat rectangular warp yarn with a rangeof 0.29-0.39 mm height by 0.35-0.52 mm width;

Round weft yarn 1003 in the cross machine direction with a diameter inthe range of 0.40 to 0.60 mm diameter;

A weave pattern with the warp yarn passing over five consecutive weftyarns then under the subsequent weft yarn, over the subsequent weftyarn, under the subsequent weft yarn, over the subsequent weft yarn,under the subsequent weft yarn then repeating the entire sequence overagain throughout the fabric, thereby resulting in an MD warp pattern of5×1×1×1×1×1. An example of a suitable fabric that has this attribute aswell as the other attributes listed here is available through Voith andis a 10× single layer (1 MD×1 CD yarns) fabric design with 10 shed weavepattern;

The warp yarns pair up side by side to create a larger bundled warp 1002equivalent to between 0.70 mm to 1.3 mm in warp yarn width to create anear continuous angled warp float or knuckle with deep and continuousvalleys or channels 1001 between the knuckles for sheet bulkdevelopment. As used herein, a channel is the depressed region betweenridges. Ridges are the top plane of compressed fiber. The measured depthof the fabric channels 1001 is in the range of 0.60 mm-0.80 mm;

The measured warp yarn angle 1005 is between 5 to 25 degrees;

The mesh (warp filaments per cross direction distance) is 17 filamentsper centimeter or less with a count (weft filaments per machinedirection distance) of 13 filaments per centimeter or less. Fabrics with6×2×3×2 (1 MD yarn over 6 CD yarns under 2 CD yarns over 3 CD yarnsunder 2 CD yarns and repeats) with 13 count mesh may also be used. Anyfabric with first warp line of 5 or more may be used to create the longwarp knuckle (for example as shown in U.S. Pat. Nos. 5,832,962;5,925,217; 6,039,838, the contents of which are incorporated herein byreference in their entirety).

FIG. 4 shows an absorbent structure, generally designated by referencenumber 300, according to an exemplary embodiment of the presentinvention made using a TAD fabric having the above-listed attributes.The absorbent structure 300 includes substantially continuous channels301 and ridges 302. More specifically, the channels 301 formed in asurface of the absorbent structure 300 extend across the surface in anunbroken manner. The weave pattern raises and bundles pairs of the warpmonofilaments in nearly continuous or unbroken lines such that thesheet/web is compressed along these lines when pressed between theYankee and pressure roll. Surprisingly, these continuous compressedportions or ridges have shown to increase the strength of the sheetcompared to conventional woven structuring fabrics. This allows lowerbasis weights to be utilized to achieve higher strength products withouthaving to over-mechanically refine or add excessive strength chemistry,which could destroy absorbency (if wet strength resins are utilized) ofthe structure and both negatively affect softness.

Additionally, the channels provide for greater absorbency, thus reducingthe need to utilize excessive rush transfer to increase bulk and provideabsorbency. As widely known in the art, a differential velocity transfer(wire crepe, wet crepe, rush transfer) can be utilized between a carrierfabric and transfer fabric, as taught in U.S. Pat. No. 4,440,597. Morecommonly, in the TAD process the carrier fabric is termed the innerwire, and the transfer fabric is termed the structuring fabric. Whenrunning the inner wire at a higher velocity than the structuring fabric,the embryonic web, which is low consistency (typically in the low 20%solids range), is forced further into the structuring fabric to develophigher bulk (and thus absorbency) than would otherwise be realizedwithout the differential velocity transfer. Increasing velocitydifferential has the negative affect of decreasing the web tensile andburst strength. In order to regain lost strength, refining of the fibersmust be increased to enhance fiber to fiber bonding, or increasedchemical strength additives must be utilized, which negatively affectsoftness and drives up energy and chemical costs. Additionally,differential velocity transfer reduces speed, thus leading to loss ofproduction. Speed differential in the dry end or dry crepe results insimilar negative effects as wet crepe.

The level of wire crepe or dry crepe used is typically proportional tothe MD stretch (i.e., MD stretch increases with the amount of wire crepeused) although MD stretch can be influenced by other factors such asfiber type, structuring fabric design, and creping conditions at theYankee dryer. The parameter of MD stretch itself can be important ashigher MD stretch typically increases tensile and ball burst strengthand even softness, if wire crepe is not used to generate the increase.However, the compressed portions provided by the bundled warp inaccordance with exemplary embodiments of the present invention give nearcontinuous ridges of strength to improve ball burst strength, and thuswire crepe can be eliminated or minimized. The ridges also provide forcontinuous zones of creping to improve sheet flexibility and overallsoftness. The depth and width of the channels 301 formed in theabsorbent structure 300 using the TAD fabrics having the above-mentionedattributes are in the range of 0.60-0.80 mm, with angles of the ridges303 between 5 to 25 degrees measured from the true machine direction.

The absorbent structure produced in accordance with exemplaryembodiments of the present invention exhibits surface attributesincluding Y Connected Area (or Y Connected Pit Area) of greater than20%, or between 8% and 50%, or 15% to 50%, or 20% to 50%, and SurfaceChannel Spacing (Ssm-x) of less than 2.5 mm, or from 0.4 to 1.2 mm, 1.2mm to 4.0 mm, or from 1.2 mm to 3.0 mm, or from 1.2 mm to 2.5 mm. YConnected Area is shown in FIG. 12 and is defined as the percentcompressed portions of the web, that run in the machine direction (Ydirection) of the web, the entire distance across the sample field ofview of 12.1 mm (X direction) by 9.1 mm (Y direction). Without beingbound by theory, it is believed higher Y Connected Area, up toapproximately 50%, would be desirable for building these compressedzones or ridges for improved strength, softness, and absorbency. Withgreater than 50% Y Connected Area, the compressed ridges would begin tobecome wide enough where wicking or capillary action begins to decreaseliquid uptake into the absorbent structure to reduce overall absorbency.Capillary action works when the channels are sufficiently small that thecombination of surface tension of the liquid and adhesive forces betweenthe liquid and fibrous material of the absorbent structure act to propelthe liquid even in opposition to external forces such as gravity.Additionally, a Y Connected Area greater than 50% could produce aproduct with such a high number of compressed ridges that the productwould feel flat and not provide a preferred bulky and soft feel in thehand of the consumer. It is also believed that keeping small spacingbetween the compressed ridges (Ssm-x value) would produce an absorbentstructure with a finer surface that feels smoother and softer in thehands of the consumer, and thus a low Surface Channel Spacing valuebelow 2.5 mm is preferred.

Use of the inventive structuring or TAD fabric allows for a highabsorbency disposable towel product to be produced with high strength(due to the near continuous warp monofilament design previouslymentioned) and absorbency (due to the channels and ridges in theproduct), and high softness due to the absence or minimization of wirecrepe and continuous zones of creped product improving flexibility. Allof this can be accomplished without excessive amounts of basis weightwhich can increase absorbency, softness, and strength but dramaticallyincrease raw material costs. The lamination process improves thestrength further by tightly adhering multiple plies of the web to form alaminate.

After the through air drying stage, the absorbent structure inaccordance with exemplary embodiments of the present invention may befurther dried in a second phase using a Yankee drying drum. In anexemplary embodiment, a creping adhesive is applied to the drum prior tothe absorbent structure contacting the drum. The absorbent structureadheres to the drum and is removed using a wear resistant coated crepingblade with a creping shelf of 0.5 mm or less. The creping doctor set upangle is preferably 10 to 35 degrees, while the blade bevel ispreferably 55 to 80 degrees. To further illustrate the creping process,FIG. 5 shows a conventional art creping blade application wherein acreping blade 1 is pressed against a steam heated drum 3 in order tocrepe a tissue web 2. The blade may be provided with a wear resistantmaterial 4 at the blade tip. The distance of the creping shelf 15 is thesame as the thickness of the creping blade 14. In comparison, as shownin FIG. 6, in accordance with exemplary embodiments of the crepingprocess used for the present invention, the distance of the crepingshelf 15 has been reduced to 0.5 mm or less by beveling thenon-contacting face of the blade 12. The angle of the bevel b isselected to obtain the desired creping shelf distance. Without beingbound by theory, it has been discovered that distance of the crepingshelf can influence the properties of the absorbent structure includingtensile, bulk, and softness since the distance of the creping shelfdirectly influences the contact time between the blade and web and thusthe forces imparted to the web by the blade. In an exemplary embodimenta 25 degree blade set up angle (c), which is measured from a normal lineat the contact point between the blade tip and the drum to the face ofthe creping blade, a wear resistant coated tip blade with an 80 degreeblade bevel (d), and a 0. 5 mm creping shelf distance is utilized.

The wear resistant material is suitably a ceramic material, a cermetmaterial, or a carbide material. For example, the wear resistantmaterial may be selected from metal oxides, ceramic materials,silicates, carbides, borides, nitrides, and mixtures thereof. Particularexamples of suitable wear resistant materials are alumina, chromia,zirconia, tungsten carbide, chromium carbide, zirconium carbide,tantalum carbide, titanium carbide, and mixtures thereof. Thewear-resistant material may be applied by thermal spraying, physicalvapor deposition, or chemical vapor deposition.

According to an exemplary embodiment of the invention, a ceramic coatedcreping blade is used to remove the absorbent structure from the Yankeedrying drum. Ceramic coated creping blades result in reduced adhesivebuild up and aid in achieving higher run speeds. Without being bound bytheory, it is believed that the ceramic coating of the creping bladesprovides a less adhesive surface than metal creping blades and is moreresistant to edge wear that can lead to localized spots of adhesiveaccumulation. The ceramic creping blades allow for a greater amount ofcreping adhesive to be used, which in turn provides improved sheetintegrity and faster run speeds.

The absorbent structure may then be calendered in a subsequent stagewithin the calendar section as shown in FIG. 2. According to anexemplary embodiment, calendaring may be accomplished using a number ofcalendar rolls that deliver a calendering pressure in the range of 0-100pounds per linear inch (PLI). In general, increased calendering pressureis associated with reduced caliper and a smoother tissue surface.Additionally, gap calendaring can be utilized where there exists a gapbetween the top and bottom calendar roll that is equal to or less thanthe thickness of the absorbent structure passing between these rolls.

In addition to the use of wet end additives, the absorbent structure inaccordance with exemplary embodiments of the present invention may alsobe treated with topical or surface deposited additives. Examples ofsurface deposited additives include softeners for increasing fibersoftness and skin lotions. Examples of topical softeners include but arenot limited to quaternary ammonium compounds, including, but not limitedto, the dialkyldimethylammonium salts (e.g. ditallowdimethylammoniumchloride, ditallowdimethylammonium methyl sulfate, di(hydrogenatedtallow)dimethyl ammonium chloride, etc.). Another class of chemicalsoftening agent include the organo-reactive polydimethyl siloxaneingredients, including amino functional polydimethyl siloxane, zincstearate, aluminum stearate, sodium stearate, calcium stearate,magnesium stearate, spermaceti, and steryl oil.

To enhance the strength and absorbency of the absorbent structure,multiple plies are laminated together using, for example, a heatedadhesive, as described below with respect to FIG. 3. The adhesivemixture is preferably water soluble and includes a mixture of one ormore adhesives, one or more water soluble cationic resins and water. Theone or more adhesives are present in an amount of 1% to 10% by weight ofthe mixture and may be selected from polyvinyl alcohol, polyvinylacetate, starch based resins and/or mixtures thereof. A water solublecationic resin may be present in an amount of up to 10% by weight of themixture and may include polyamide-epichlorohydrin resins, glyoxalatedpolyacrylamide resins, polyethyleneimine resins, polyethylenimineresins, and/or mixtures thereof. The remainder of the mixture iscomposed of water.

FIG. 3 shows an apparatus for manufacturing a laminate of two plies of astructured paper towel or tissue that are joined to each other, with theYankee side surface of each ply facing the exterior of the laminatedstructure, in accordance with an exemplary embodiment of the presentinvention. The process illustrated in FIG. 3 is referred to as dynamicembossment knock out (DEKO) embossing. As shown, two webs 200, 201 ofsingle ply towel which may be manufactured, for example, according tothe methods described herein are plied together with only one web beingembossed. A first web 200 is fed through a nip 202A formed by rubbercovered pressure roll 203 and embossing roll 204 (also known as apatterned roll). The embossing roll 204 which rotates in the illustrateddirection, impresses an embossment pattern onto the web 200 as it passesthrough the nip between emboss roll 204 and pressure roll 203. A secondweb 201 is fed across two idler rolls 205 and joins with web 200 at thenip between the embossing roll 204 and marrying roll 214. The idlersrolls can be driven. Alternatively, the emboss section may not haveidler rolls in which case the second web would travel directly to thenip between the embossing roll 204 and marrying roll 214.

After being embossed, the top ply may have a plurality of embossmentsprotruding outwardly from the plane of the ply towards the adjacent ply.The emboss roll 204 has embossing tips or embossing knobs that extendradially outward from the rolls to make the embossments. In theillustrated embodiment, embossing is performed by the crests of theembossing knobs applying pressure onto the rubber pressure roll andcompressing and deflecting web 200 into the pressure roll 203 andthereby imparting the imprint of the embossments into the paper web.

An adhesive applicator roll 212 is positioned upstream of emboss roll204 and is aligned in an axially parallel arrangement with the embossroll. The heated adhesive is fed from an adhesive tank 207 via a conduit210 to applicator roll 212. The applicator roll 212 transfers heatedadhesive to an interior side of embossed ply 200 to adhere the at leasttwo plies 200, 201 together, wherein the interior side is the side ofply 200 that comes into a face-to-face relationship with ply 201 forlamination. The adhesive is applied to the ply at the crests of theembossing knobs on embossing roll 204. In a preferred exemplaryembodiment, the adhesive is applied only to the tips of the embossmentsin the ply 200.

Notably, in exemplary embodiments of the present invention, the adhesiveis heated and maintained at a desired temperature utilizing, inembodiments, the adhesive tank 207, which is an insulated stainlesssteel tank that may have heating elements 208 that are substantiallyuniformly distributed throughout the interior heating surface. In thismanner, a large amount of surface area may be heated relativelyuniformly. Generally, an adjustable thermostat may be used to controlthe temperature of the adhesive tank 207. It has been found advantageousto maintain the temperature of the adhesive at between approximately 32degrees C. (90 degrees F.) to 66 degrees C. (150 degrees F.), andpreferably to around 49 degrees C. (120 degrees F.). In addition, inembodiments, the tank has an agitator 209 to ensure proper mixing andheat transfer.

After the application of the embossments and the adhesive, a marryingroll 214 is used to apply pressure for lamination. The marrying roll 214forms a nip with the embossing roll 204. The marrying roll 214 isgenerally needed to apply pressure to the two webs to allow the adhesiveon the crests of the embossments on web 200 to contact and adhere to andlaminate to web 201.

The specific pattern that is embossed on the absorbent products issignificant for achieving the enhanced scrubbing resistance of thepresent invention. In particular, it has been found that the embossedarea on the top ply should cover between approximately 5 to 15% of thesurface area. Moreover, the size of each embossment should be betweenapproximately 0.04 to 0.08 square centimeters. The depth of theembossment should be within the range of between approximately 0.127 and0.43 centimeters (0.050 and 0.170 inches) in depth.

The emboss pattern used is also important to provide adequate area forbonding the laminate while limiting absorbency loss, as the laminatedareas will absorb less than the non-laminated areas. In a preferredexemplary embodiment, the embossed area on any ply should be in therange of 5 to 15%. The size of each embossment is preferably in therange of 0.04 to 0.08 square centimeters. The depth of each embossmentis preferably in the range of 0.05 and 0.170 inches.

The combination of the structuring fabric and lamination method providesa disposable towel product with a unique combination of high levels ofsoftness, ball burst strength, and absorbency with low levels of MDstretch.

Ball Burst Testing

The Ball Burst of a 2-ply tissue web was determined using a TissueSoftness Analyzer (TSA), available from emtec Electronic GmbH ofLeipzig, Germany using a ball burst head and holder. A punch was used tocut out five 100 cm² round samples from the web. One of the samples wasloaded into the TSA, with the embossed surface facing down, over theholder and held into place using the ring. The ball burst algorithm wasselected from the list of available softness testing algorithmsdisplayed by the TSA. The ball burst head was then pushed by the TSAthrough the sample until the web ruptured and calculated the grams forcerequired for the rupture to occur. The test process was repeated for theremaining samples and the results for all the samples were averaged.

Stretch & Md, Cd, and Wet Cd Tensile Strength Testing

An Instron 3343 tensile tester, manufactured by Instron of Norwood,Mass., with a 100N load cell and 25.4 mm rubber coated jaw faces, wasused for tensile strength measurement. Prior to measurement, the Instron3343 tensile tester was calibrated using Operator's Guide M10-16279-EMRevision D. After calibration, 8 strips of 2-ply product, each 2.54 cmby 10.16 cm (one inch by four inches), were provided as samples for eachtest. When testing MD (Material Direction) tensile strength, the stripswere cut in the MD direction. When testing CD (Cross Direction) tensilestrength, the strips were cut in the CD direction. One of the samplestrips was placed in between the upper jaw faces and clamp, and thenbetween the lower jaw faces and clamped with a gap of 5.08 cm (2 inches)between the clamps. A test was run on the sample strip to obtain tensilestrength and stretch. The test procedure was repeated until all thesamples were tested. The values obtained for the eight sample stripswere averaged to determine the tensile strength of the tissue. Whentesting CD wet tensile, the strips were placed in an oven at 105 degreesCelsius for 5 minutes and saturated with 75 microliters of deionizedwater evenly across the cross direction at the center of the stripimmediately prior to pulling the sample.

Basis Weight

Using a dye and press, six 76.2 mm by 76.2 mm square samples were cutfrom a 2-ply product being careful to avoid any web perforations. Thesamples were placed in an oven at 105 deg C. for 5 minutes before beingweighed on an analytical balance to the fourth decimal point. The weightof the sample in grams was divided by (0.0762 m)² to determine the basisweight in grams/m².

Caliper Testing

A Thwing-Albert ProGage 100 Thickness Tester, manufactured by ThwingAlbert of West Berlin, N.J. was used for the caliper test. The ThicknessTester was used with a 2 inch diameter pressure foot with a presetloading of 0.93 grams/square inch. Eight 100 mm×100 mm square sampleswere cut from a 2-ply product. The samples were then tested individuallyand the results were averaged to obtain a caliper result for the basesheet.

Softness Testing

Softness of a 2-ply tissue web was determined using a Tissue SoftnessAnalyzer (TSA), available from Emtec Electronic GmbH of Leipzig,Germany. The TSA comprises a rotor with vertical blades which rotate onthe test piece to apply a defined contact pressure. Contact between thevertical blades and the test piece creates vibrations which are sensedby a vibration sensor. The sensor then transmits a signal to a PC forprocessing and display. The frequency analysis in the range ofapproximately 200 to 1000 Hz represents the surface smoothness ortexture of the test piece and is referred to as the TS750 value. Afurther peak in the frequency range between 6 and 7 kHz represents thebulk softness of the test piece and is referred to as the TS7 value.Both TS7 and TS750 values are expressed as dB V² rms. The stiffness ofthe sample is also calculated as the device measures deformation of thesample under a defined load. The stiffness value (D) is expressed asmm/N. The device also calculates a Hand Feel (HF) number with the valuecorresponding to a softness as perceived when someone touches a tissuesample by hand (the higher the HF number, the higher the softness). TheHF number is a combination of the TS750, TS7, and stiffness of thesample measured by the TSA and calculated using an algorithm, which alsorequires the caliper and basis weight of the sample. Differentalgorithms can be selected for different facial, toilet, and towel paperproducts. Before testing, a calibration check should be performed using“TSA Leaflet Collection No. 9” (dated 2016 May 10) available from Emtec.If the calibration check demonstrates a calibration is necessary, “TSALeaflet Collection No. 10” is followed for the calibration procedureavailable from emtec dated 2015 Sep. 9.

A punch was used to cut out five 100 cm² round samples from the web. Oneof the samples was loaded into the TSA, clamped into place (outwardfacing or embossed ply facing upward), and the TPII algorithm wasselected from the list of available softness testing algorithmsdisplayed by the TSA. After inputting parameters for the sample(including caliper and basis weight), the TSA measurement program wasrun. The test process was repeated for the remaining samples and theresults for all the samples were averaged and the average HF numberrecorded.

Method for Data Capture for Surface Analysis Including Y Connected Areaand Surface Channel Spacing

Images used to calculate the Y Connected Pit Area and Surface ChannelSpacing Along X Axis (Ssm-x) were acquired using a Keyence Model VR-3200G2 3D Macroscope equipped with motorized XY stage, VR-3000K controller,VR-H2VE version 2.2.0.89 Viewer software, and VR-H2AE Analyzer software.After following calibration procedures, as outlined by the Keyenceequipment manual from 2016, the instrument was configured for 25×magnification. The following was selected on the viewer software:“Expert mode” for viewer capture method, and “normal” capture image typefor Camera settings. For Measurement settings: “Glare removal” mode wasselected with “both sides” measurement direction, Adjust brightness formeasurement set to “Auto,” and Display missing and saturated data turned“ON.” This results in a “3D surface data set” which is approximately12.1 mm (X direction) by 9.1 mm (Y direction) with a pixel size ofapproximately 7.9 microns.

On paper towel, the top surface of the top ply is the surface ofinterest, avoiding any and all emboss points if possible. Embossmentsare not representative of the majority of the surface and should beavoided during the “3D surface data set” acquisition. A representativepaper towel sheet was torn from the center of a roll and held in placeusing weights. When tearing the sheet from the roll, care was taken soas to not alter the topographic features of the sample. The machinedirection (MD) of the sample was placed in the Y axis (front to back onthe stage as seen from operator perspective in front of the system)while the cross direction (CD) was placed in the X axis (left to righton the stage as seen from operator perspective in front of the system).Care was taken to ensure no creases or folds were present in the sampleand the sample was not under any MD or CD directional stress. The imagewas autofocused prior to capturing the “3D surface data set”. Ten ofthese “3D surface data sets” were collected for each sample.

“3D surface data sets” were exported from the analyzer software withimage type “Height” and the “No Skip” option selected. These “3D surfacedata sets” were analyzed with OmniSurf3D (v1.01.052) software, availablefrom Digital Metrology Solutions, Inc. of Columbus, Ind., USA forparameter calculations.

The OmniSurf 3D settings were set as follows:

-   -   Preprocessing:    -   Alignment—Auto-trim to Valid    -   Edge Discarding—Use all data,        -   Outlier Removal—None    -   Missing Data Filling—Linear Fill        -   Data Inversion—None        -   Transform        -   Rotate—0        -   Geometry:    -   Reference Geometry—Polynomial        -   X-order=4        -   Y-order=4        -   Filtering:    -   Short Wavelength Limitation—Gaussian/0.80000 mm/Sync X&Y    -   Long Wavelength Limitation-Gaussian/8.00000 mm/Sync X&Y        -   Post-Filter Edge Discarding—None

The Pre-processing settings are shown in FIG. 9. The Geometry Settingsare shown in FIG. 10. The Filtering settings are shown in FIG. 11.

The settings described above were chosen to remove underlying curvaturesin the samples. The desired exported file from the Keyence software wasopened in the Omnisurf 3D software. In the “analysis” menu, “parameters”was selected, and Ssm-x was chosen. The user clicked “OK” and the Ssm-xvalue was recorded. For Y-Connectivity Pit Area, the “Pit/PorosityAnalysis” tool was selected in the “Tools” menu. “Height Above Meanline”was chosen and the height was set to 0. The user clicked “Apply” and theY-Connectivity Pit Area was recorded.

Method for Determining Texture Aspect Ratio

The towel of the present invention exhibits a unique texture aspectratio (Str) as defined in ISO 25178-2 (2012) and shown in FIG. 13 whichis a parameter that defines the ratio of the shortest autocorrelationlength to the longest autocorrelation length across the surface of anobject.

In the case of paper towel or tissue, the product will have longer andnarrower ridge-like structures across the surface of the product and,therefore, a lower Str parameter. Without being bound by theory, atissue or towel product with a lower Str parameter would therefore, haveridges that should be able to remove and retain a greater amount ofcontamination. In the case of a tissue product, this would allow forimproved enhanced cleaning of a contaminated surface such as acountertop. FIG. 4 shows an example of a surface with a low Str valueand the ridge-like structures that are developed.

Images used to calculate the Str parameter were acquired using a KeyenceModel VR-3200 G2 3D Macroscope equipped with motorized XY stage,VR-3000K controller, VR-H2VE version 2.2.0.89 Viewer software, andVR-H2AE Analyzer software. After following calibration procedures, asoutlined by The Keyence equipment manual from 2016, the instrument wasconfigured for 25× magnification. The following was selected on theviewer software: “Expert mode” for viewer capture method, and “normal”capture image type for Camera settings. For Measurement settings: “Glareremoval” mode was selected with “both sides” measurement direction,Adjust brightness for measurement set to “Auto,” and Display missing andsaturated data turned “ON.” This results in a “3D surface data set”which is approximately 12.1 mm (X direction) by 9.1 mm (Y direction)with a pixel size of approximately 7.9 microns.

On paper towel, the bottom surface of the bottom ply is the surface ofinterest. This surface is chosen due to the lack of embossments.Embossments are not representative of the majority of the surface andshould be avoided during the “3D surface data set” acquisition. Arepresentative paper towel sheet was torn from the center of a roll andheld in place using weights. When tearing the sheet from the roll, carewas taken so as to not alter the topographic features of the sample. Themachine direction (MD) of the sample was placed in the Y axis (front toback on the stage as seen from operator perspective in front of thesystem) while the cross direction (CD) was placed in the X axis (left toright on the stage as seen from operator perspective in front of thesystem). Care was taken to ensure no creases or folds were present inthe sample and the sample was not under any MD or CD directional stress.The image was autofocused prior to capturing the “3D surface data set”.Ten of these “3D surface data sets” were collected at random positionson the towel sheet.

“3D surface data sets” were exported from the analyzer software withimage type “Height” and the “No Skip” option selected. These “3D surfacedata sets” were analyzed with OmniSurf3D (v1.01.052)) software,available from Digital Metrology Solutions, Inc. of Columbus, Ind., USAfor parameter calculations.

The OmniSurf3D settings are set as follows:

-   -   Preprocessing:    -   Alignment—Auto-trim to Valid    -   Edge Discarding—Use all data,        -   Outlier Removal—None    -   Missing Data Filling—Linear Fill        -   Data Inversion—None            -   Transform            -   Rotate—0            -   Geometry:        -   Reference Geometry—Polynomial            -   X-order=4            -   Y-order=4            -   Filtering:    -   Short Wavelength Limitation—Gaussian/0.80000 mm/Sync X&Y    -   Long Wavelength Limitation—Gaussian/8.00000 mm/Sync X&Y        -   Post-Filter Edge Discarding—None

The Str parameter is calculated for each of the 10 “3D surface datasets”. The mean of these 10 Str values is reported as the “average Str”of the towel sample. The standard deviation (SD) is also reported.

Method for Determining Channel Depth

The fabric pocket depth was measured using a Keyence Model VR-3200 G2 3DMacroscope equipped with motorized XY stage, VR-3000K controller,VR-H2VE version 2.2.0.89 Viewer software, and VR-H2AE Analyzer software.After following calibration procedures, as outlined by The Keyenceequipment manual from 2016, the instrument was set to the “High Mag Cam”at 40× magnification. The following was selected on the viewer software:“Expert mode” for viewer capture method, and “depth comp” capture imagetype for Camera settings. For Measurement settings: “Superfine” mode wasselected with “both sides” measurement direction. Adjust brightness formeasurement set to “Auto,” and Display missing and saturated data turned“ON.” This results in a “3D surface data set” which is approximately 7.6mm (X direction) by 5.7 mm (Y direction).

A 6 in. by 6 in. section of the structured or TAD fabric was placed onthe sample stage and held in place by weights to assure the sample wasresting completely flat. Once the sample was in focus using the “Focusadjustment” arrows in the Viewer Software, a measurement was taken. Inthe Analyzer Software, the “Profile” tool was selected to draw a “2Point” profile line from one of the highest points of the fabric(reference number 500), across the lowest MD yarn and CD yarnintersection (reference number 501) of the fabric, to another high pointof the fabric (reference number 502) as shown in FIG. 15. The lowest MDyarn and CD yarn intersection is believed to be the lowest point of thepocket. A side view of the profile line is shown in the bottom window.Using the “Point to Point (Pt-Pt) Vertical distance” measurement tool inthe side view window of the profile line, the vertical distance wasmeasured from the highest point (reference number 503) to the lowestpoint (reference number 504).

Method for Determining Channel Angle

One sample sheet was torn from a rolled paper product along theperforation. A ruler and pen were used to draw a line that traveledalong one pocket channel and did not enter any neighboring channels asshown by reference number 401 in in FIG. 14. A protractor was placed ontop of the sample and positioned so the bottom of the protractor wasoverlaid and parallel to the perforated edge of the sample. The linerepresenting the channel angle was measured and recorded using theprotractor. 90 degrees was subtracted from the measured angle and theabsolute value was taken to determine the channel angle. As shown inFIG. 14, reference number 402 shows a measured angle of 103.7 degree,for example. After subtracting 90 degrees from this value and taking theabsolute value, a channel angle of 13.7 degrees is calculated from TrueMachine Direction (reference number 400).

Absorbency Testing

An M/K GATS (Gravimetric Absorption Testing System), manufactured by M/KSystems, Inc., of Peabody, Mass., USA was used to test absorbency usingMK Systems GATS Manual from Mar. 30, 2016. The following steps werefollowed during the absorbency testing procedure:

Turn on the computer and the GATS machine. The main power switch for theGATS is located on the left side of the front of the machine and a redlight will be illuminated when power is on. Ensure the balance is on. Abalance should not be used to measure masses for a least 15 minutes fromthe time it is turned on. Open the computer program by clicking on the“MK GATS” icon and click “Connect” once the program has loaded. If thereare connectivity issues, make sure that the ports for the GATS andbalance are correct, the GATS being attached to “COM7” and the balancebeing attached to “COMB”. These can be seen in Full Operational Mode.The upper reservoir of the TAS needs to be filled with Deionized water.The Velmex slide level for the wetting stage needs to be set at 4.5 cm.If the slide is not at the proper level, movement of it can only beaccomplished in Full Operational Mode. Click the “Direct Mode” check boxlocated in the top left of the screen to take the system out of DirectMode and put into Full Operational Mode. The level of the wetting stageis adjusted in the third window down on the left side of the softwarescreen. To move the slide up or down 1 cm at a time, the button for “1cm up” and “1 cm down” can be used. If a millimeter adjustment isneeded, press and hold the shift key while toggling the “1 cm up” or “1cm down” icons. This will move the wetting stage 1 mm at a time. Clickthe “Test Options” Icon and ensure the following set-points areinputted: “Dip Start” selected with 10.0 mm inputted under” Absorption”,“Total Weight change (g)” selected with 0.1 inputted under “Start At”,Rate (g) selected with 0.05 inputted per (sec) 5 under “End At” on theleft hand side of the screen, “Number of Raises” 1 inputted and regularraises (mm) 10 inputted under “Desorption”, Rate (g) selected with −0.03inputted per 5 sec under “End At” on the right hand side of the screen.These selections are also shown in FIG. 8. The water level in theprimary reservoir needs to be filled to the operational level before anyseries of testing. This involves the reservoir and water contained in itto be set to 580 grams total mass. Click on the “Setup” icon in the boxlocated in the top left of the screen. The reservoir will need to belifted to allow the balance to tare or zero itself. The feed and drawtubes for the system are located on the side and extend into thereservoir. Prior to lifting the reservoir, ensure that the top hatch onthe balance is open to keep from damaging the top of the balance or theelevated platform that the sample is weighed on. Open the side door ofthe balance to lift the reservoir. Once the balance reading is stable amessage will appear to place the reservoir again. Ensure that thereservoir doesn't make contact with the walls of the balance. Close theside door of the balance. The reservoir will need to be filled to obtainthe mass of 580 g. Once the reservoir is full, the system will be readyfor testing. The system is now ready to test. Obtain a minimum number offour 113 mm diameter circular samples. Three will be tested with oneextra available. Enter the pertinent sample information in the “EnterMaterial ID.” section of the software. The software will automaticallydate and number the samples as completed with any used entered data inthe center of the file name. Click the “Run Test” icon. The balance willautomatically zero itself. Place the pre-cut sample on the elevatedplatform, making sure the sample isn't in contact with the balance lid.Once the balance load is stabilized, click “Weigh”. Move the sample tothe wetting stage, centered with the emboss facing down. Ensure thesample doesn't touch the sides and place the cover on the sample. Click“Wet the Sample”. The wetting stage will drop the preset distance toinitiate absorption. The absorption will end when the rate of absorptionis less than 0.05 grams/5 seconds. When absorption stops, the wettingstage will rise to conduct desorption. Data for desorption isn'trecorded for tested sample. Remove the saturated sample and dry thewetting stage prior to the next test. Once the test is complete, thesystem will automatically refill the reservoir. Record the datagenerated for this sample. The data that is traced for each sample isthe dry weight of the sample (in grams), the normalized total absorptionof the sample reflected in grams of water/gram of product, and thenormalized absorption rate in grams of water per second. Repeatprocedure for the three samples and report the average total absorbency.

The towel of the present invention exhibits a unique Y Connectivity PitArea of greater than 20, or between 30 to 45, with Surface ChannelSpacing of less than 2.5 mm, or between 1.8 to 2.4 mm. Additionally, thechannel depth may range from 0.60 mm to 0.80 mm. Without being bound bytheory, a tissue or towel product with a high Y Connectivity Pit Areaparameter would have ridges that should be able to remove and retain agreater amount of contamination. In the case of a disposable towel, theproduct would be able to provide enhanced cleaning of a contaminatedsurface such as a countertop.

The following example illustrates advantages of the present invention.

Example 1

Paper towel made on a wet-laid asset with a three layer headbox wasproduced using the through air drying method. The imprinting orstructuring fabric had a warp monofilament of 0.35 mm diameter with aweft monofilament of 0.50 mm diameter with the weave pattern describedherein. The mesh was 16 filaments/cm while the count was 12filaments/cm. The Air Permeability was 650 cfm, 1.14 mm in caliper, witha knuckle surface that was sanded to impart 16% contact area with theYankee dryer. The flow to each layer of the headbox was about 33% of thetotal sheet. The three layers of the finished tissue from top to bottomwere labeled as air, core and dry. The air layer is the outer layer thatis placed on the TAD fabric, the dry layer is the outer layer that isclosest to the surface of the Yankee dryer and the core is the centersection of the tissue. The tissue was produced with 50% NBSK and 50%eucalyptus in the Yankee layer with 80% NBSK, 20% eucalyptus in the coreand air layer. Polyamine polyamide-epichlorohydrin resin at 12.0 kg/ton(dry basis) and 4.0 kg/ton (dry basis) of carboxymethylcellulose wereadded to each of the three layers to generate permanent wet strength.Additionally, 1.5 kg/ton of polyvinyl amine was added to each layer toaid in fiber retention with 2.0 kg of amphoteric starch for additionalstrength generation. The NBSK was un-refined. The Yankee and TAD sectionspeed was 1200 m/min running 0% slower than the forming section. TheReel section was additionally running 1% faster than the Yankee. Sheetmoisture dropped from 77% to 20% in the TAD section, requiring 22 m³ ofnatural gas per bone dry ton of paper towel produced.

The towel was then plied together using the method described hereinusing a steel emboss roll with the pattern shown in FIG. 16 andapproximately 7% polyvinyl alcohol based adhesive heated to 120 deg F. Arolled 2-ply product with DEKO emboss was produced with a core diameterof 43 mm, 135 sheets and a roll diameter of 148 mm, with each sheethaving a length of 6.0 inches and a width of 11 inches. The 2-ply tissueproduct had the following product attributes: Basis Weight 39.0 g/m²,Caliper 713 mm, MD tensile of 443 N/m, CD tensile of 318 N/m, a ballburst of 896 grams force, an MD stretch of 7.4%, a CD stretch of 11.4%,a CD wet tensile of 89.9 N/m, an absorbency of 12.9 g/g, and a TSAsoftness of 58.8. The Y Connected Area was 34.5% and Ssm-x was 2.04 mm.The Str value was 0.0974 with a standard deviation of 0.00191. Thechannel angle was about 13.7 deg, using a fabric with a channel depth of0.698 mm. FIG. 4 shows an image magnified at 40 times of the surface ofthe disposable towel produced in this Example. The ridges formed in thedisposable towel results in the high Y-Connectivity parameter.

Example 2

Paper towel made on a wet-laid asset with a three layer headbox wasproduced using the through air drying method. The imprinting orstructuring fabric used a weave pattern described herein, 12.0 yarn/cmMesh and Count, 0.35 mm diameter warp monofilament, 0.50 mm diameterweft monofilament, 1.29 mm caliper, 670 cfm and a knuckle surface thatwas sanded to impart 12% contact area with the Yankee dryer. The flow toeach layer of the headbox was about 33% of the total sheet. The threelayers of the finished tissue from top to bottom were labeled as air,core and dry. The air layer is the outer layer that is placed on the TADfabric, the dry layer is the outer layer that is closest to the surfaceof the Yankee dryer and the core is the center section of the tissue.The tissue was produced with 16.7% eucalyptus, 50% northern bleachedsoftwood kraft (NBSK) fibers, and 33% re-pulped “broke” fibers which area combination of eucalyptus and NBSK fibers reused from off-grade towelparent rolls. The dry layer fiber was 50% eucalyptus, 50% NBSK while thecore and air layer were 50% NBSK, 50% broke. Polyaminepolyamide-epichlorohydrin resin at 8.5 kg/ton (dry basis) and 2.8 kg/ton(dry basis) of anionic polyacrylamide were added to each of the threelayers to generate permanent wet strength. The core layer had 2 kg/tonof starch added. The NBSK was refined separately before blending intothe layers using 45 kwh/ton on two conical refiners connected in series.The Yankee and TAD section speed was 1450 m/min running 11% slower thanthe forming section. Sheet moisture dropped from 77% to 20% in the TADsection, requiring 24 m{circumflex over ( )}3 of natural gas per bonedry ton of paper towel produced.

The towel was then plied together using DEKO emboss the method describedherein using a steel emboss roll with the pattern shown in FIG. 16 and7% polyvinyl alcohol based adhesive heated to 120 deg F. A rolled 2-plyproduct was produced with a 43 mm diameter core, 146 sheets and a rolldiameter of 147 mm, with each sheet having a length of 6.0 inches and awidth of 11 inches. The 2-ply tissue product had the following productattributes: Basis Weight 42.7 g/m², Caliper 0.831 mm, MD tensile of 403N/m, CD tensile of 412 N/m, a ball burst of 1087 grams force, an MDstretch of 10%, a CD stretch of 8%, a CD wet tensile of 123 N/m, anabsorbency of 14.2 g/g, and a TSA softness of 48.3. The Y-Connected Areawas 21.5% with a Ssm-x of 2.15 mm. The Str value was 0.1022 with astandard deviation of 0.00389. The channel angle was about 16.5 deg,using a fabric with a channel depth of 0.752 mm.

Comparative Example

Paper towel made on a wet-laid asset with a three layer headbox wasproduced using the through air drying method. A TAD fabric design namedProlux 593 supplied by Albany (216 Airport Drive Rochester, N.H. 03867USA Tel: +1.603.330.5850) was utilized. The fabric had a 45 yarns/inchMesh and 27 yarns/inch Count, a 0.35 mm diameter warp monofilament, a0.55 mm diameter weft monofilament, a 1.89 mm caliper, with a 670 cfmand a knuckle surface that is sanded to impart 15% contact area with theYankee dryer. The flow to each layer of the headbox was about 33% of thetotal sheet. The three layers of the finished tissue from top to bottomwere labeled as air, core and dry. The air layer is the outer layer thatis placed on the TAD fabric, the dry layer is the outer layer that isclosest to the surface of the Yankee dryer and the core is the centersection of the tissue. The tissue was produced with 50% NBSK and 50%eucalyptus in the yankee layer with 80% NBSK, 20% eucalyptus in the coreand air layer. Polyamine polyamide-epichlorohydrin resin at 12.0 kg/ton(dry basis) and 4.0 kg/ton (dry basis) of carboxymethylcellulose wereadded to each of the three layers to generate permanent wet strength.Additionally, 1.5 kg/ton of polyvinyl amine was added to each layer toaid in fiber retention with 2.0 kg of amphoteric starch for additionalstrength generation. The NBSK was refined separately before blendinginto the layers using 100 kwh/ton on one conical refiner. The Yankee andTAD section speed was 1200 m/min running 17% slower than the formingsection. The Reel section was additionally running 1% faster than theYankee. Sheet moisture dropped from 77% to 20% in the TAD section,requiring 28 m{circumflex over ( )}3 of natural gas per bone dry ton ofpaper towel produced.

The towel was then plied together using the DEKO method described hereinusing a steel emboss roll with the pattern shown in FIG. 16 and 7%polyvinyl alcohol based adhesive heated to 120 deg F. A rolled 2-plyproduct was produced with a 43 mm core, 146 sheets and a roll diameterof 147 mm, with each sheet having a length of 6.0 inches and a width of11 inches. The 2-ply tissue product had the following productattributes: Basis Weight 39.9 g/m², Caliper 0.880 mm, MD tensile of 429N/m, CD tensile of 491 N/m, a ball burst of 1098 grams force, an MDstretch of 21.4%, a CD stretch of 13.3%, a CD wet tensile of 146 N/m, anabsorbency and 15.9 g/g, and a TSA softness of 44.4. The Y ConnectedArea was 0% with a Ssm-x of 3.06 mm. The Str value was 0.6856 with astandard deviation of 0.0414. There was no channel angle in the paperderived from using this fabric, but rather discrete pockets ordiscontinuous depressions imprinted that match the pattern of thestructuring fabric.

FIG. 7 shows the surface parameters and physical properties of theComparative Example and various commercially available disposable towelproducts compared to the inventive product.

Now that embodiments of the present invention have been shown anddescribed in detail, various modifications and improvements thereon willbecome readily apparent to those skilled in the art. Accordingly, thespirit and scope of the present invention is to be construed broadly andnot limited by the foregoing specification.

1. A two-ply, through air dried disposable paper towel productcomprising: a laminate of at least two plies, wherein the product has ameasured Y-Connected Area parameter greater than 20, a Surface ChannelSpacing of less than 2.5 mm, and a CD wet tensile strength of greaterthan 80 N/m.
 2. The paper towel product of claim 1, wherein the producthas a ball burst to MD stretch ratio of greater than
 100. 3. The papertowel product of claim 1, wherein the product has an absorbency to MDstretch ratio of greater than 1.2.
 4. The paper towel product of claim1, wherein (ball burst X absorbency)/MD stretch of the product has avalue greater than
 1250. 5. The paper towel product of claim 1, whereinthe paper towel product comprises a surface having channels, and thechannels have a channel angle between 5 and 25 degrees.
 6. The papertowel product of claim 1, wherein the paper towel product comprises asurface having channels, and the channels have a channel depth between0.60 mm to 0.80 mm.
 7. The paper towel product of claim 1, wherein theproduct has an Str value less than 0.15.
 8. The paper towel product ofclaim 1, wherein the paper towel product comprises a surface havingchannels, and the product has an Str value of less than 0.15 and achannel angle greater than 2 degrees.